Lasers have been a great training aid for my wife, sort of a crutch when she first started shooting. Past that, I dont feel that they are reliable enough to depend on for self defense. Batteries can go dead, ambient light can be too bright, just too much can go wrong. It was a great help for me, trying to see why she was shooting the way she did, and helped reenforce the muscle memory involved with point shooting.
When it all comes down though, I still depend on sight alignment, sight picture teaching mt primary marksmanship instructor beat into us in boot camp. It works, as long as my sights are attached, wont let me down, and with good training, becomes second nature to the user.